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Triangles: Isosceles

In the figure below, what is the value of $$xº$$ ? ![](data:image/svg+xml;base64,<?xml version="1.0" encoding="utf-8"?>
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Incorrect. [[snippet]]
Correct. [[snippet]] Since angles $$DCB$$ and $$DCE$$ are supplementary, >$$\angle DCB = 180º - 170º= 10º$$. Because $$\triangle BCD$$ is isosceles, $$\angle DBC = 10º$$ as well. You can find third angle in $$\triangle BCD$$ by subtracting: >$$\angle BDC = 180º - 2(10º) = 160º$$. Given that angles $$ADB$$ and $$BDC$$ are also supplementary angles, >$$\angle ADB = 180º - 160º = 20º$$. Since $$\triangle ABD$$ is isosceles, $$\angle DAB = 20º$$ also. Finally, you have two angles in $$\triangle ABD$$, so you can find the third by subtracting: >$$x = 180º - 2(20º) = 140º$$.
Incorrect. [[snippet]]
Incorrect. [[snippet]]
Incorrect. [[snippet]]
10°
20°
80°
140°
160°